There are three levels of file permissions: read, write and execute. In addition, there are three groups to which you can assign permissions: file owner, user group and everyone. The command chmod followed by three numbers is used to change permissions. The first number is the permission for the owner, the second for the group and the third for everyone. Here are how the levels of permission translate:

0 = ---

No permission

1 = --X

Execute only

2 = -W-

Write only

3 = -WX

Write and execute

4 = R--

Read only

5 = R-X

Read and execute

6 = RW-

Read and write

7 = RWX

Read, write and execute

It is preferred that the group always have permission of 0. This prevents other users on the server from browsing files via Telnet and FTP. Here are the most common file permissions used:

chmod 604 [filename]

Minimum permissions for HTML file

chmod 705 [directory name]

Minimum permissions for directories

chmod 755 [filename]

Minimum permissions for scripts & programs

chmod 606 [filename]

Permissions for data files used by scripts

chmod 703 [directory name]

Write-only permissions for public FTP uploading

How do I unzip a file with telnet?

All of the below commands assume that you are within the same directory that the compressed file is in. To be sure type: ls {enter} If the file is there, you're ready to go. If not type: cd /big/dom/xdomain/www/directory/ {enter} replacing the path with the correct path to your file.

The zip command compresses a file or list of files into a zip format archive file. This command is compatible with pkzip on a PC. Simply type "zip zipfile file1 file2 file3" at a telnet command prompt and replace zipfile with the name you want to use for your compressed zip archive file, and replace fileX with the name of the file(s) you want to compress into the zip archive.

For example, type "zip backup.zip home.html index.html" at a telnet command prompt to compress and archive the files called home.html and index.html into the file called backup.zip.

unzip [options] [zipfile]

The unzip command extracts a zip format archive file. This command is compatible with pkunzip files from a PC. Simply type "unzip zipfile" at a telnet command prompt and replace zipfile with the name of your zip format archive file.

For example, type "unzip -aL old.zip" at a telnet command prompt to extract files contained in the archive called old.zip. The "-aL" are options that are generally useful when unzipping files created on a PC.